The present invention relates to duct connecting structures.
Conventionally, inkjet recording devices are broadly known as a type of liquid ejection device. The inkjet recording devices include so-called off-carriage types in which an ink retaining body provided in an ink cartridge is connected to a recording head provided along the bottom surface of a carriage through an ink supply tube. This type of recording device pressurizes the ink retaining body by supplying pressurized air into the ink cartridge with a pressurization pump or the like. As pressurized, the ink retaining body presses and moves the ink retained in the ink retaining body to flow to the recording head through the ink supply tube, which is formed of polyethylene or the like. The recording head is thus supplied with ink. The ink is ejected toward a recording paper sheet as ink drops, through a nozzle opening of the recording head provided in the carriage, which reciprocates, thus performing recording (see, for example, Japanese Laid-Open Patent Publication No. 2001-212974).
There is a demand for minimization of ink jet type recording devices as a whole. For meeting the demand, the ink supply tube is formed of flexible material such as elastomer. When the carriage is reciprocated, the ink supply tube is bent by a large amount for saving the space for moving the tube. When joining the ink supply tube with a connecting member connected to the ink retaining body, a sleeve projecting from the connecting member is fitted into a hole defined in the tube. This structure prevents separation between the ink supply tube and the connecting member. Further, since the ink supply tube is formed of elastomer, the tube is relatively soft and thus functions as a seal.
However, such softness makes it easier for the ink supply tube of elastomer to be deformed due to creep or by external force. The deformation of the ink supply tube produces a gap between the sleeve and the connecting hole, resulting in lowering of the seal performance between the ink supply tube and the connecting member.